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ECE :: Measurements and Instrumentation

  1. The full-scale deflection current of an ammeter is 1 mA and its internal resistance is 100°hm. This is to have full deflection when 100V is measured. What is the value of series resistor to be used?

  2. A.

     99.99 K ohms

    B.

     100 K ohms

    C.

     99.99 ohms

    D.

     100 ohms

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  3. A spring controlled indicating instrument has a deflection of 90deg for maximum current I. The corresponding deflection for a gravity controlled instrument is

  4. A.

     90°

    B.

     120°

    C.

     30°

    D.

     0°

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  5. PMMC type instruments normally use

  6. A.

     Air friction damping

    B.

     Fluid friction damping

    C.

     Eddy current damping

    D.

     None of the above

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  7. Jewels are used in instruments for the purpose of

  8. A.

     Damping

    B.

     Torque control

    C.

     Suppressing noise

    D.

     Bearing

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  9. Which instrument has identical calibration for ac as well as dc values?

  10. A.

     Hot wire type

    B.

     Moving coil type

    C.

     Induction type

    D.

     Moving iron type

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  11. The full-scale deflection current of an ammeter is 1 mA and its internal resistance is 100°hm. If this meter is to have full deflection at 5A, what is the value of the shunt resistance to be used?

  12. A.

     49.99 Ohms

    B.

     1/49.99 ohms

    C.

     1 Ohm

    D.

     2 Ohms

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  13. If the instrument is to have a wide range, the instrument should have

  14. A.

     Linear scale

    B.

     Square-law scale

    C.

     Exponential scale

    D.

     Logarithmic scale

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  15. It can be stated that

  16. A.

     CT operates at almost the same flux density as a PT

    B.

     CT operates with a higher flux density than PT

    C.

     CT operates with considerably lower flux density than a PT

    D.

     No generalisation can be made with regard to the flux densities in CT and PT

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  17. To measure an A. C. voltage by using an A.C. potentiometer, it is desirable that the supply for the potentiometer in taken

  18. A.

     From a source which is not the same as the unknown voltage

    B.

     From a battery

    C.

     From the same source as the unknown voltage

    D.

     Any of the above

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  19. With a sweep time 10ms across the screen the approx. horizontal sawtooth frequency will be

  20. A.

     50Hz

    B.

     100Hz

    C.

     1kHz

    D.

     500Hz

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